The Primary Breast Cancer Therapy Group (NSABP) was established in 1958 and now has 104 affiliated institutions, 21 of which are granted. The membership consists of 328 surgical, 244 medical and 127 radiation oncologists. There are also 140 pathologists, immunologists and endocrinologists. The Operations Office and Biostatistical Center employs 61 persons in positions ranging from data clerks to physicians and statisticians. Contributing members are supported by 238 nurses and data collectors. The NSABP objectives are: (a) to assess the worth of new and promising therapies when employed either alone or in concert with other modalities for the treatment of such tumors, (b) to allow for evaluation of the worth of modalities presently employed in the treatment of such cancers when used in innovative ways to test current biological hypotheses, (c) to gather biological and other pertinent data so as to better understand the natural history of patients with such tumors and to permit formulation of better strategies for their treatment, (d) to permit formulation of interventions that could enhance the quality of life of breast cancer patients, and (e) to improve the quality of care of breast cancer patients through the process of educating physicians to the findings and experiences of this group. Since August, 1971, eleven protocols have been implemented to evaluate therapy in Stages I and II breast cancer. As of December, 1981, 7689 eligible patients meeting common protocol requirements have been accrued; 6184 (80%) were alive and being followed with 1600 actively receiving therapy. During 1981 those patients generated approximately 60,000 forms and materials requiring processing by the Biostatistical Center. The present application is submitted so that efforts toward fulfilling the above documented objectives may be continued. The specific aims are to: (1) complete patient accrual in Protocol Nos. B-06, 11, 12, 13 and 14, (b) continue follow-up in all protocols, (3) design and implement successor protocols, (4) design and perform special studies relating to biological considerations associated with NSABP protocols, (5) extend quality control procedures, (6) perform data analyses, and (7) develop and implement methodological investigations associated with cross-protocol comparisons.